Thanks Jim, I think it's important to understand how drum brakes work for better assembly.
God knows, I've seen every combination of mismatched shoes on a wheel; two primary or secondary shoes on the same wheel, primary shoe on the wrong side, etc. Some guys never knew there was a difference and couldn't understand why their new brakes pulled so badly.
But in fairness, nobody can actually see drum brakes function. That makes it harder to understand what's really happening. - Dave